Stick type personal care products comprise a stick of a waxy gel-like compound, which may be used as a deodorant, lipstick, or any other form of skin care products. The standard type of container for such products comprises a cylindrical tube or sleeve, with a removal cap at one end, and a movable interior plug at the other end. As the stick becomes used, the plug can be moved up the cylindrical container, so as to extend the end of the stick out of the container.
Generally speaking two types of extension systems are available. In the one case, a threaded screw is provided within the stick of the product, and a rotary knob is provided at the lower end of the container. The knob is connected to the screw. As the knob is rotated, the screw also rotates, and this causes the stick of material to be gradually extended from the container. Usually, such a system will incorporate a plug, which is threaded on to the threaded rod, and as the rod is located the plug is forced up through the tubular container.
The other common type of extension system is a lower cost simpler system in which a moveable plug is provided in the bottom of the container, and the bottom of the container is left open. A finger, or a rod such as a pencil can be inserted in the open end of the tube, and the plug is pushed up, thereby extending the stick of product from the tube.
This is obviously a less expensive mechanism, and while it suffers from the minor disadvantage that if excessive pressure is placed on the end of the stick while the product is being applied to the skin, the stick may slide back into the tube, it nevertheless is found to function satisfactorily for most purposes.
The existence of these two different systems can however create problems for the manufacturer.
The cost of the containers and packaging for such skin care products constitutes a major portion of the total cost of the item, and manufacturers are always seeking ways to reduce the packaging cost as far as possible so long as it does not impair the function of the product. The labelling of such products is usually applied by silk screening or hot stamping on the outside of the container, and this too adds significantly to the cost of the package.
In addition, the storage of such containers until they are filled and shipped out from the plant represents a significant expense to the manufacturer.
Where for example two different forms of containers are required: one for the screw-threaded type of dispenser; and the other for the pressure plug type of dispenser; then this will significantly increase the manufacturing costs of the product.
It is therefore desirable if possible that the tubular containers shall be capable of being used with both forms of dispenser that is to say both with a screw-threaded type of dispenser and also with a pressure plug type of dispenser. This will substantially reduce the manufacturing costs, since it will be possible to manufacture the tubes, and label them, in greater numbers at any given time, thereby obtaining significant economies in mass manufacture, and in addition, it will be possible to reduce the numbers of containers required to be kept in storage thereby adding to the savings achieved.
Another significant factor in this type of container is the effectiveness of the seal between the plug at the bottom end of the container and the inner side walls of the container. The containers are usually filled with the product in a semi-liquid state, and the product then sets in the container. Consequently, it is essential to provide an effective seal at the lower end of the container, so that the product while it is being filled does not escape around the plug. This creates undesirable results for the purchaser who may then have to clean up the container before using the product.
It is therefore apparent that whichever type of ejection mechanism is used, whether it be screw-threaded, or pressure plug, the seal between the plug and the container must be effective so as to reduce or eliminate these problems.